The present invention relates to the medical field, and more particularly to a treatment for a pulmonary disease involving chronic obstruction of the airways, to a nebulizer apparatus for delivery of the medication, and to a treatment kit therefor.
1. Addington W R, Stephens R E, Gilliland K, Rodriguez M. Assessing the laryngeal cough reflex and the risk of developing pneumonia after stroke. Arch Phys Med Rehabil. 1999;80:150-4.
2. Addington W R, Stephens R E, Gilliland K A. Assessing the laryngeal cough reflex and the risk of developing pneumonia after stroke: an interhospital comparison. Stroke. 1999;30:1203-7.
3. Tomori Z, Stransky A. Electroneurographic and pneumotachographic analysis of the expiration reflex. Physiol Bohemoslov. 1973;22:589-601.
4. Fujimura M, Sakamoto S, Kamio Y, Matsuda T. Cough receptor sensitivity and bronchial responsiveness in normal and asthmatic subjects. Eur Respir J. 1992;5:291-5.
5. Fujimura M, Sakamoto S, Kamio Y, Saito M, Miyake Y, Yasui M, Matsuda T. Cough threshold to inhaled tartaric acid and bronchial responsiveness to methacholine in patients with asthma and sino-bronchial syndrome. Intern Med. 1992;31:17-21.
6. Addington W R, Stephens R E, Ockey R R, Kann D, Rodriguez M. A new aspiration screening test to assess the need for modified barium swallow study [abstract]. Arch Phys Med Rehabil. 1995;76:1040.
7. Widdicombe J G. Reflexes from the upper respiratory tract. Bethesda, Md.: The American Physiological Society; 1986.
8. Addington W R, Stephens R E, Gilliland K, Miller S P. Tartaric acid-induced cough and the superior laryngeal nerve evoked potential. Am J Phys Med Rehabil. 1998;77:523-6.
9. Sakamoto S, Fujimura M, Kamio Y, Saito M, Yasui M, Miyake Y, Matsuda T. [Relationship between cough threshold to inhaled tartaric acid and sex, smoking and atopy in humans]. Nihon Kyobu Shikkan Gakkai Zasshi. 1990;28:1478-81.
10. Fujimura M, Sakamoto S, Kamio Y, Matsuda T. Sex difference in the inhaled tartaric acid cough threshold in non-atopic healthy subjects. Thorax. 1990;45:633-4.
11. Tomori Z, Widdicombe J G. Muscular, bronchomotor and cardiovascular reflexes elicited by mechanical stimulation of the respiratory tract. J Physiol (Lond). 1969;200:25-49.
12. Sant""Ambrogio G, Widdicombe J. Reflexes from airway rapidly adapting receptors. Respir Physiol. 2001;125:33-45.
13. Addington W R, Stephens R E, Goulding R E. Anesthesia for the superior laryngeal nerves and tartaric acid-induced cough. Arch Phys Med Rehabil. 1999;80:1584-6.
14. Coleridge J C, Coleridge H M. Afferent vagal C fibre innervation of the lungs and airways and its functional significance. Rev Physiol Biochem Pharmacol. 1984;99:1-110.
15. Widdicombe J G. Afferent receptors in the airways and cough. Respir Physiol. 1998 October;114:5-15.
16. Widdicombe J. Airway receptors. Respir Physiol. 2001;125:3-15.
17. Widdicombe J G. Chemoreceptor control of airways. Respir Physiol. 1992 Mar;87:373-81.
18. Youtsey J W. Egan""s Fundamentals of Respiratory Care. In: Egan D F, Scanlan C L, Spearman C B, Sheldon R L, eds. 5th/ed. St. Louis: Mosby; 1990:p. 387.
The laryngeal cough reflex (LCR) and its precursor, the laryngeal cough expiratory reflex (LCER), are primal, brainstem mediated reflexes that have been shown in humans to protect the upper airway from the aspiration of potentially harmful material into the lungs. [1,2]
The LCER, when stimulated via the inhalation of a composition of tartaric acid, triggers a cascade of neurological events which ultimately results in the contraction of the abdominal and intercostal muscles to produce an initial expiration in an attempt to clear the abnormal aspirant. This is followed by a series of more forceful coughs with inspiratory and expiratory components (LCRs). [3]
There has been limited research performed on the use of inhaled tartaric acid to induce cough in asthmatic subjects. A study by Fujimura and coworkers showed that the cough threshold to tartaric acid did not differ between normal and asthmatic subjects and found that there was no correlation between cough threshold and bronchial responsiveness, supporting the hypothesis that cough and bronchoconstriction are separate airway reflexes. [4,5] No prior studies that we are aware of have fully described the effects of inhaled tartaric acid on the pulmonary function parameters in asthmatics.
Over the past seven years we have tested the LCER/LCR with nebulized compositions of tartaric acid (the reflex cough test, or RCT) to assess the integrity of the subjects"" defensive mechanisms and thus to decide the appropriate treatment regime to avoid aspiration pneumonia in patients with cerebral damage. The RCT has also been performed in normal subjects and in patients with multiple co-morbidities, including asthma and COPD. [1,2,6] There have been no obvious adverse events related to this chemoirritant, and we therefore expected that pulmonary function parameters would not significantly change in either the normal or an asthmatic group after inhalation of the tartaric acid composition. However, laryngeal irritation is known to cause reflex bronchoconstriction, mucosal vasodilatation and excess mucus secretion. [7] Accordingly, one would expect the mechanical effects of the first two but not the last to subside quickly. In addition, the violent respiratory movements of coughing could perturb airway function. Thus, there is the potential for adverse changes as the result of tartaric acid inhalation, and we theorized that these might be detected through pulmonary function tests (PFT).
The original intent of this investigation, therefore, was to determine parameters fo use of objective PFTs in examining the effects of tartaric acid-induced cough on pulmonary function in normal healthy and asthmatic individuals. Outcome measures included specific pulmonary functions, and the occurrence of airway obstruction or bronchospasm.
With the foregoing in mind, the present invention advantageously provides a nebulizer apparatus for treatment of a patient having a pulmonary disease involving chronic obstruction of the airways. The apparatus is adapted for self-treatment by the patient, and comprises a container sized to be portable by the patient and having therein a chamber containing a composition comprising a pharmaceutically acceptable carrier mixed with L-tartaric acid. A nebulizing valve having an opening connected to the chamber is positioned so as to provide an outlet therefor, and a source of motivating force connected with the chamber so as to motivate the composition through the opening in the nebulizing valve to thereby cause nebulization of the composition. In the apparatus, nebulization comprises droplets having an airborne diameter of less than about 10 xcexcm, and the L-tartaric acid is mixed in the composition in an amount effective for causing an increase in peak respiratory flow when inhaled by the patient.
The invention also includes a method for treatment of a patient having a pulmonary disease involving chronic obstruction of the airways. The method comprises inhalation by the patient of a nebulized composition comprising a pharmaceutically acceptable carrier mixed with L-tartaric acid in an amount effective for causing an increase in peak respiratory flow. The pharmaceutically acceptable carrier preferably comprises a solution having at least about 0.15 M sodium chloride, and at least about 20% L-tartrate.
A treatment kit is adapted for self-treatment by a patient having a pulmonary disease involving chronic obstruction of the airways. The kit comprises a container sized to be portable by the patient, and containing a pharmaceutically acceptable carrier mixed with L-tartaric acid in an amount effective for causing an increase in peak respiratory flow when inhaled by the patient, a nebulizing valve connected to the chamber, and a source of pneumatic pressure to motivate the composition through the valve to thereby generate a nebulized composition comprising droplets having an airborne diameter of less than about 10 xcexcm. The kit also includes a generally tubular mouthpiece connectable to the container so as to be in fluid connection with the nebulizing valve to convey the nebulized composition into a patient""s mouth for oral inhalation by the patient. Optionally, the kit may also comprise a removable cap fitting over the mouthpiece, a nose clip to aid the patient in oral inhalation of the composition, and a respiratory flow meter for determining increase in peak respiratory flow.